Effect of Different Vegetation Types on Runoff Generation of Slope Land in Jinyun Mountains of Chongqing City

To study the effects of different vegetation types on runoff generation on slope land in the Three Gorges reservoir area of the Yangtze River,4 standard runoff plots with different vegetation types were laid out in the Jinyun Mountains,Chongqing City.The different vegetation types included mixed broadleaf—conifer forest,broad-leaved forest,Phyllostachys pubescens forest,and shrub.Rainfall and surface runoff from the plots were measured.Results show that vegetation types,in terms of the averaged value of surface runoff depth,were ranged in the order of Phyllostachys pubescens forest broad-leaved forest mixed broadleaf—conifer forest shrub.Surface runoff depths for the vegetation types are found to be 3.094,1.972,1.751,and 1.170 mm.The amount of surface runoff in selected arbor forestlands is smaller than that in Phyllostachys pubescens forest and significant difference in the amount of surface runoff does not exist in mixed broadleaf—conifer forest,broad-leaved forest,and shrub.The correlation between rainfall amount and surface runoff in forestlands is significant and the correlation between rainfall intensity and surface runoff in forestlands are not notable.Under the same rainfall condition,the variation tendencies of surface runoff in these types of forestlands are different and the amount of surface runoff in Phyllostachys pubescens forest is always the largest.